Adjustable Vehicle Seat Suspension

ABSTRACT

An adjustable seat suspension for a vehicle seat that includes a linkage arrangement disposed between a seat frame and seat base whose collapse is opposed by a spring lever arm linkage arrangement supported on a fluid powered spring actuator carried by the base that has a plurality of pivotable spring lever arms that are each coupled to a portion of the frame. In a preferred embodiment, the fluid powered spring actuator is an air spring whose pressure is adjustable and which is powered by an air compressor to tailor suspension characteristics and provide a desired preload. The base includes an upright to which the spring lever arm linkage arrangement is pivotally mounted with its spring lever arms supported by a saddle carried by the air spring at a location disposed between the upright and where the spring lever arms couple with the seat suspension.

FIELD

The present invention relates to adjustable seat suspensions,particularly for vehicles including off-road vehicles, which provides asupporting biasing force that is adjustable over a wide weight range andmore particularly to an adjustable seat suspension capable of doing sousing a fluid-powered drive arrangement.

BACKGROUND

Off road equipment such as lift trucks, skid steer loaders, compactexcavators, and the like, often utilize a spring supported seat toisolate the seat occupant from vibration during vehicle operation. Suchcushioning usually utilizes extension or compression springs whichsupport the occupant's weight. However, because the range of the seatoccupant's weight is often in excess of 150 pounds and because of therelatively confined space in these types of vehicles available for theseat, it is not only difficult to configure a seat suspension that fitsin such a small space but it is also a challenge to “tune” a springsupported seat suspension to provide optimum comfort. Accordingly, ithas been known to employ seat suspensions utilizing extension orcompression springs wherein the biasing force imposed by the springs onthe seat structure is adjustable.

U.S. Pat. No. 5,601,338 discloses a vehicle seat structure that includesa mechanical spring type adjustable vehicle seat suspension. In thispatent, the seat is pivoted at its forward edge, and the rear edge issupported by a pair of extension springs. An adjustable slide locatedupon a lever arm is interposed between the springs and the rear seatportion where the position of the slide is adjusted to vary the extentof spring biasing force by changing the location of the application ofthe biasing force relative to the lever. While this adjustable seatsuspension construction enables adjustment for a wide weight range ofvehicle operators, only the forward pivoting seat bottom is suspended,which reduces the effectiveness of the suspension system and results inrelative motion between the occupant and seat backrest. This can cause avehicle operator to experience unwanted discomfort during use andoperation.

U.S. Pat. No. 6,186,467 discloses an improved adjustable mechanicalspring type seat suspension where the entire seat frame is mounted on ascissors linkage and supported by the suspension. By linking the seatframe to the suspension, both the seat back and seat bottom move inunison during suspension operation, comfort is enhanced because bothoccupant support and vibration isolation is improved. The vehiclesuspension is also adjustable such that it can be adjusted for a limitedrange of vehicle operator weights.

While these compact mechanical spring type vehicle seat suspensionsprovide relatively low collapsed height, are compact in size, and arerelatively economical in cost and maintenance, improvements nonethelessremain desirable. For example, vehicle operator adjustment of amechanical spring type seat suspension can be challenging, particularlywhile the vehicle operator is sitting. In addition, as the vehicleoperator weights continue to increase, mechanical spring type seatsuspensions are not readily configurable to provide support and enableadjustment over an increasingly wider weight adjustment range.

What is needed is an improved vehicle seat suspension which is wellsuited for use in vehicle seat suspension application where a low seatindex point (SIP) is required or desired, which offers improved ease ofadjustment along with a greater adjustment range, and which is adaptablefor use in a wide variety of seating applications.

SUMMARY

The present invention is directed to a vehicle seat equipped with asuspension that is coupled to and which resiliently supports a frame ofthe seat. The suspension includes a fluid powered actuator, such as anair spring, which cooperates with a spring lever arm linkage operativelycoupled to the seat frame. The air spring is carried by a seat base thathas an upright extending upwardly and rearwardly of the air spring andat least a portion of the seat frame. The spring lever arm linkage isgenerally U-shaped, having a rod that is pivotally mounted to theupright and a pair of spring lever arms that extend outwardly alongeither side of the air spring which are coupled to a portion of the seatframe. The air spring is operatively connected to each spring lever armat a location between where the spring lever arm linkage pivotallymounts to the upright and where the spring lever arms couple to the seatframe. In a preferred embodiment, a generally U-shaped spring saddlemounts on the spring and has a pair of downwardly extending arms thateach carry a roller upon which a curved section of a correspondingspring arm rides helping to ensure vertical air spring translationduring suspension operation.

A fluid powered drive, such as an air compressor, is in fluid flowcommunication with the fluid powered actuator. Where the fluid powereddrive is an air compressor and the fluid powered actuator is an airspring, at least one conduit is employed to communicate air from the aircompressor to the air spring. In a preferred embodiment, a manipulablecontrol is used to control inflation and/or deflation of the air spring,such as by controlling air compressor operation and/or venting of airfrom the air spring. In a preferred embodiment, the manipulable controlis a knob that can be manipulated by seat occupant while seated toadjust air pressure in the air spring, such as for increasing ordecreasing preload. As a result, weight adjustment is enabled.

The suspension can include a damper, such as a hydraulic cylinder typedamper, that extends between the spring saddle and the upright. Such adamper arrangement can be configured to provide vertical translationduring suspension operation in a manner where the telescoping rod of thedamper is extended at a velocity proportional to the velocity of theseat frame, thereby exerting an upward force on the seat frame and seatoccupant. The suspension also includes a linkage arrangement that isdisposed between the base and the seat frame that cooperates with othercomponents of the suspension to facilitate relative movement between theseat frame and base during operation. In a preferred embodiment, thelinkage arrangement is a scissors linkage arrangement that includes apair of scissors linkages that are spaced apart and operativelyconnected to the seat frame and base.

In a preferred embodiment, each spring lever arm extends outwardly fromthe upright and has a portion that overlies a corresponding rollercarried by the spring saddle mounted on the air spring and anotherportion at or adjacent its free end that underlies part of a bottom seatframe supporting the seat frame thereon. In a preferred embodiment, anend of each spring lever arm engages a cradle that underlies atransversely extending cross brace of the bottom seat frame. Such acradle can be formed of one or more pads fixed to the cross brace andconfigured to receive or otherwise engage a portion of the free end of acorresponding spring lever arm. During suspension operation, an upwardbiasing force of the air spring acting on each spring lever arm imposesan upward biasing force upon the seat frame providing resilient supportfor the seat frame and a seat occupant that also opposes scissors armlinkage collapse.

A suspension constructed in accordance with the present inventionemploys a seat frame assembly that is an integral part of the suspensionassembly. The seat frame is directly coupled to the seat base by thescissors linkage arrangement with each spring lever arm acting directlyupon the seat frame assembly as a result of being upwardly biased by theair spring carried by the seat base. By coupling the seat frame directlyto the scissors linkage, a secondary seat frame mounting plate commonlyused in “under the seat” vehicle seat suspensions of relatively lowprofile vehicle seat constructions is eliminated. In addition, thisarrangement advantageously provides an integrated seat and suspensionassembly having a low seat index point (SIP) that is capable ofreplacing a standard static, non-suspended seat suspension in manyapplications.

Other features and advantages of the invention will become apparent tothose skilled in the art from the following detailed description andaccompanying drawings. It should be understood, however, that thedetailed description and specific examples, while indicating thepreferred embodiments of the present invention, are given by way ofillustration and not of limitation. Many changes and modifications maybe made within the scope of the present invention without departing fromthe spirit thereof, and the invention includes all such modifications.

DRAWINGS DESCRIPTION

Preferred exemplary embodiments of the invention are illustrated in theaccompanying drawings in which like reference numerals represent likeparts throughout, and in which:

FIG. 1 is a front perspective exploded view of a vehicle seat equippedwith a seat suspension constructed in accordance with the presentinvention that resiliently supports a seat frame of the seat;

FIG. 2 is a fragmentary side elevation view of the seat frame explodedfrom a seat base that carries the seat suspension with a portion of aseat suspension upright sidewall removed for clarity;

FIG. 3 is a front perspective view of the seat base and seat suspension;

FIG. 4 a rear perspective view of the seat base and seat suspension; and

FIG. 5 is a front perspective exploded view of the seat suspension.

Before explaining embodiments of the invention in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and the arrangement of the components set forthin the following description and illustrated in the drawings. Theinvention is capable of other embodiments or being practiced or carriedout in various ways. Also, it is to be understood that the phraseologyand terminology employed herein is for the purpose of description andshould not be regarded as limiting.

DETAILED DESCRIPTION

FIGS. 1-5 illustrate a vehicle seat 20 without any seat cushions shownthat includes a seat frame 22 coupled to a base 24 by a preferredembodiment of a vehicle seat suspension 26 that is constructed inaccordance with the present invention. The suspension 26 includes ascissors linkage arrangement 28 interposed between the frame 22 and thebase 24 and a fluid powered biasing arrangement 30 carried by the base24 that operatively cooperates with a spring lever arm linkagearrangement 32 that engages the frame 22 in a manner that opposesscissor linkage collapse and that supports a seat occupant sitting inthe seat 20. A vehicle seat suspension 26 constructed in accordance withthe present invention advantageously not only improves ease ofadjustability, it also is capable of supporting seat occupants, e.g.,vehicle operators, having a greater range of weights. Such a vehicleseat suspension 26 is advantageously well-suited for use in a widevariety of vehicles, including off-road vehicles, watercraft, and thelike.

The scissors linkage 28 includes a pair of spaced apart and fore-aftextending scissors links that each has an inner scissors arm 34 and anouter scissors arm 36 connected by a pivot 38 that allows relativerotation therebetween. The inner scissors arms 34 are interconnected bya transversely extending rod 40 disposed adjacent to the front of theseat 20. Likewise, the outer scissors arms 36 are also interconnected bya transversely extending rod 42. Each inner scissors arm 34 has a lowerend pivotally received in a bearing block 44 held captive in a retainerchannel 46 attached to a pan or plate 48 of the base 24 adjacent thefront of the seat 20. Each inner scissors link arm 34 has an upper endequipped with an outturned pivot 50 that is rotatively coupled to abearing tube 52 that extends inwardly from part of the seat frame 22.Each outer scissors link arm 36 has a lower end that is held pivotallycaptive by a tab 54 that extends upwardly from the base plate 48. Eachouter scissors link arm 36 has an upper end that is pivotally receivedin a bearing block 56 held captive in a retainer channel 58 attached topart of the seat frame 22 adjacent the front of the seat 20. It will beappreciated that the scissors linkage 28 can be operatively connected tothe seat frame 22 and base 24 using a different configuration than thatdiscussed above and shown in the drawing figures.

The seat frame 22 is shown in FIGS. 1 and 2 as having a bottom seatframe 60 that generally underlies the thighs and buttocks of a seatoccupant (not shown) and a seat back frame 62 connected to the bottomseat frame 60 by a pair of hinge brackets 64 that permit the seat backto be folded or otherwise pivoted forwardly. The bottom seat frame 60also includes an outer frame rail 66 interconnected by at least onebrace 68 defining a bottom seat frame 60 that is also capable ofsupporting a seat cushion (shown in phantom in FIG. 2). The seat backframe 62 includes an outer frame rail 70 interconnected by at least onebrace 72 defining a seat back frame 62 that can support a seat backcushion (not shown). While the frame rails and interconnecting braces ofthe seat frame 22 are shown in FIGS. 1 and 2 as being of tubularconstruction, it should be appreciated that other frame rail and bracetypes and configurations can be used. It also should be noted that otherseat frame configurations can also be used.

The base plate 48 is grounded to the chassis or frame of the vehicle(not shown) in which the vehicle seat 20 is mounted. The base plate 48is shown in the drawing figures as being equipped with a pair ofoutwardly extending flanges 74, each of which is adapted for receiving aseat slide (not shown) or another type of fore-aft adjustment device.Where equipped with seat slides, each seat slide grounds the base 24 tothe vehicle chassis or frame in a manner that permits fore-aft seatposition adjustment. An example of such a seat base plate equipped withseat slides is disclosed in commonly owned U.S. Pat. No. 6,186,467, theentire disclosure of which is hereby expressly incorporated herein byreference. Where seat slides are not used, the base plate 48 can bedirectly grounded to the vehicle chassis or frame, such as by beingdirectly attached thereto. For example, the base plate 48 can beattached using fasteners (not shown), such as bolts, rivets, or thelike.

Inboard of the base plate flanges 74 adjacent the front of the seat 20is a fluid powered drive 76 that is connected by a conduit 77 (FIG. 5)to the fluid powered biasing arrangement 30, which is shown mounted on apedestal 78 attached to the base plate 48. In a currently preferredembodiment, the fluid powered biasing arrangement 30 is an air springand the fluid powered drive 76 is an air compressor. The air compressor76 is electrically powered, such as by being connected to an electricalsystem of the vehicle. Adjustment of the pressure of the air in the airspring 30 can be performed by a seat occupant while sitting in the seat20 via an adjustment knob 80 mounted to a plate 82 carried by a frontportion of outer frame rail 66.

In a preferred embodiment, such as is depicted in FIG. 5, manipulationof the adjustment knob 80, such as by rotation or displacement of theknob, configures a valve 81 disposed fluid flow communication, e.g., inconduit 77, between the air compressor 76 and the air spring 30 in amanner that selectively increases or decreases inflation and/or pressureof the air spring 30. In this manner, adjustment can be performed toincrease or decrease the amount of resistance the air spring 30 providesin resisting collapse of the scissors linkage 28 in response to a loadapplied to the suspension 26 thereby correspondingly increasing ordecreasing the amount of suspension preload.

Due to the relative ease by which the adjustment knob 80 can bemanipulated by a seat occupant, including in particular when they areseated, a suspension 26 constructed in accordance with the presentinvention advantageously improves ease of spring preload or weightadjustment over the prior art. In addition, due to the increasedcapacity of the air spring 30, a greater range of preload or weightadjustability is provided thereby producing a suspension 26 constructedin accordance with the present invention that advantageously is able toprovide suspension support to seat occupants having a greater weightrange than the prior art. For example, in one preferred embodiment, theair spring 30 is selected to provide suspension support to a seatoccupant having a weight greater than 350 pounds. In another preferredembodiment, the air spring is selected to provide suspension support toa seat occupant having a weight as much as or greater than 400 pounds.

Inboard and adjacent each upturned scissors linkage pivot receiving tab54 is a suspension supporting upright 84 that extends upwardly from thebase plate 48 adjacent the rear of the seat 20. In the preferredembodiment shown in the drawing figures, the upright 84 is fixed to thebase plate 48. The upright 84 includes a generally vertically extendingrear wall 86 and a pair of tapered edge sidewalls 88 that generallyencircle or encompass the air spring 30. With specific reference toFIGS. 3-5, the rear wall 86 of the upright 84 is constructed with acutout 90 for accommodating a portion of the generally cylindrical airspring 30 located adjacent the wall 86. In addition, the rear wall 86includes a pair of apertures 92 through which a corresponding springlever arm 94 of the lever arm linkage 32 forwardly extends. Eachaperture 92 is oval or oblong having a length that accommodates therange of vertical pivotal motion of the spring lever arm 94 extendingtherethrough.

As is also best shown in FIGS. 3-5, each spring lever arm 94 of thelever arm linkage 32 is interconnected by a transversely extending rod96 defining a lever arm linkage 32 of generally U-shaped construction.The spring lever arm interconnecting rod 96 is pivotally anchored to therear wall 86 by a pair of bearing straps 98 that each holds the rod 96captive against a bearing block 100 and the rear wall 86. If desired,the rear wall 86 can also include a pair of spaced apart spring recesses102 (FIG. 4) formed in it along with mechanical spring hook receivingnotches 104 (FIG. 4) thereby enabling the base plate and upright to beused with either the fluid driven seat suspension 26 of the presentinvention or the extension spring based seat suspension disclosed incommonly owned U.S. Pat. No. 6,186,467 enabling the base to beconstructed so as to be advantageously adaptable for use with eithertype of seat suspension in a common assembly line.

The rear wall 86 of the suspension supporting upright 84 also can beequipped with a forwardly extending damper mounting bracket 106 that hasa pivot 108 to which one end of a damper 110 can be pivotally mounted.Where a damper 110 is used, the other end of the damper 110 can bepivotally mounted to a pivot 112 that extends outwardly from a generallyU-shaped spring saddle 114 that overlies the top of the air spring 30.During suspension operation, the damper 110 dampens vibration, shocksand bumps communicated to it through the air spring 30 to ground via theupright 84 and base plate 48.

As is shown in FIG. 5, the spring saddle 114 overlies a spacer or washer116 that overlies the air spring 30 through which an air inlet port 118extends that is ultimately in fluid flow communication with the aircompressor 76. With additional reference to FIGS. 2 and 3, the saddle114 has a generally horizontal portion 120 that overlies the spacer 116and ultimately the air spring 30 such that the saddle 114 displacessubstantially in unison with the air spring 30, e.g. with springdeflection. The saddle 114 also has a pair of downwardly extending arms122, 124 with the damper pivot 112 mounted to arm 122. Each saddle arm122, 124 has an outwardly extending pivot 126 that rotatively carries aroller 128 upon which a corresponding one of the spring lever arms 94 ofthe spring lever arm linkage arrangement 32 rides. Each spring lever arm94 can and preferably does have an arcuate roller seating segment 130that seats on roller 128. This curved roller seating segment 130 of eachspring lever arm 94 is configured to advantageously help ensure verticaltranslation of the air spring 30 during suspension operation. The outerprofile or contour of the roller 128 can be and preferably issubstantially complementary with the spring lever arm 94, which has agenerally circular cross sectional shape.

As is best shown in FIG. 2, the free end of each spring lever arm 94 hasa necked down portion 132 that is telescopically receivable in acorresponding one of a pair of spaced apart and generally parallel bores134 formed in a suspension coupling cradle 136 that is attached to crossbrace 68 of the bottom seat frame 60 thereby coupling the seat frame 22to the suspension 26 in a manner where the entire frame 22 is supportedby the suspension 26. While the suspension coupling cradle 136 is shownin the drawing figures as being a single elongate pad, it can also beimplemented as a pair of pads.

The suspension coupling cradle 136 preferably is fixed to cross brace 68and underlies a bottom surface of the cross brace 68 in the manner shownin FIG. 2. The free end 132 of each spring lever arm 94 engages thecoupling cradle 136 forwardly of the air spring 30 and a fulcrum of thespring lever arm linkage 32 located where the linkage 32 pivots in thebearing block 100 thereby providing mechanical advantage based upon thelength of the moment arm between the pivot point and coupling cradle136. As a result, vertical displacement of the air spring 30 duringsuspension operation, such as due to air spring deflection in responseto an applied load, a jolt, a bump or the like, correspondinglydisplaces the seat frame 24 due to its coupling via coupling cradle 136to each spring lever arm 94. Because of the intermediate location ofeach roller 128 that underlies and supports part of a correspondingspring lever arm 94, a moment is created by the air spring 30 beingcaptured in compression that opposes a downward moment caused by a seatoccupant with the spring 30 being sufficiently compliant enough andhaving a desired spring rate that desirably reduces the magnitude ofsuch an applied load, jolt or bump. In addition, particularly when thisarrangement is used in combination with a damper 110, desirablevibration isolation results from a suspension 26 constructed inaccordance with the present invention.

During operation, a vehicle equipped with a vehicle seat 20 having asuspension 26 constructed in accordance with the present inventionencounters jolts, bumps and the like that are better dampened andisolated by the suspension. During operation, a downward force due tothe weight of a seat occupant sitting on the seat is exerted on or abouteach end of each spring lever arm 94 produces a moment that is opposedby a force exerted generally in an opposite direction by the air spring30 being operatively connected to the spring lever arms 94 via thespring saddle 114. Should the downward force exerted at or about theends of the spring lever arms 94 change, a corresponding rapid increaseor decrease in the pressure within the air spring 30 occurs therebyproviding a counteracting suspension response. As a result, suspensionperformance is improved due to increased speed of response and improvedisolation. As a result of the ability of the air spring 30 to increaseits air pressure in response to an abrupt increase in the applied force,such as due to a jolt, bump or the like, it advantageously automaticallyand rapidly better isolates them from the seat occupant.

When it is desired to increase suspension preload, adjustment knob 80 ismanipulated in a manner that causes the air compressor 76 to supplyadditional air so as to increase the air pressure within the air spring30 thereby making the air spring 30 stiffer. While this can also makethe suspension 26 stiffer or less compliant, it preferably is used by aseat occupant to better tailor the characteristics of the suspension 26to the desires of the seat occupant, preferably by providing an adequateamount of weight adjustment for seat occupant comfort. For example, fora seat occupant having a greater weight, increasing air pressure withinthe air spring 30 advantageously increases preload in a manner thatprovides better suspension operating characteristics for such a heavierseat occupant. Conversely, the adjustment knob 80 can also bemanipulated to release air from the air spring 32, decreasing the airpressure within the air spring 30 to make the air spring more compliant.While this can also make the suspension 26 softer, it preferably canalso be used to better tailor the suspension preload for the weight of alighter seat occupant.

Various alternatives are contemplated as being within the scope of thefollowing claims particularly pointing out and distinctly claiming thesubject matter regarded as the invention. For example, while a singleair spring is disclosed, more than one air spring can be used. It isalso to be understood that, although the foregoing description anddrawings describe and illustrate in detail one or more preferredembodiments of the present invention, to those skilled in the art towhich the present invention relates, the present disclosure will suggestmany modifications and constructions, as well as widely differingembodiments and applications without thereby departing from the spiritand scope of the invention.

1. A vehicle seat suspension for a vehicle seat comprising: (a) a base;(b) a seat frame; (c) a fluid powered seat suspension arrangement inoperable cooperation with the seat frame and the base.
 2. The vehicleseat suspension of claim 1 wherein the fluid powered suspensionarrangement comprises a fluid powered actuator carried by the base thatis operatively connected with a pivotable linkage arrangement that isoperatively connected to the seat frame.
 3. The vehicle seat suspensionof claim 2 further comprising an upright extending upwardly from thebase, wherein the seat frame has a seat portion and a seatback portion,and wherein the pivotable linkage arrangement is pivotally attached tothe upright and pivotally operatively connected to the seat portion ofthe seat frame.
 4. The vehicle seat suspension of claim 3 furthercomprising a fluid drive in communication with the fluid poweredactuator and an arrangement enabling selective adjustment of the fluidpowered actuator.
 5. The vehicle seat suspension of claim 4 wherein thefluid powered actuator comprises an air spring, the fluid is air, andthe fluid drive comprises a compressor.
 6. The vehicle seat suspensionof claim 1 wherein the fluid powered suspension arrangement comprises afluid powered actuator, a saddle that is displaceable by the fluidpowered actuator, and a pivotable spring arm linkage in operativecooperation with the saddle and the seat frame.
 7. The vehicle seatsuspension of claim 6 wherein the seat frame has a seat portion and aseatback portion and the spring arm linkage is generally U-shaped andhas a pair of arms extending outwardly therefrom that are eachoperatively connected to the seat portion of the seat frame.
 8. Thevehicle seat suspension of claim 7 wherein displacement of the saddle bythe fluid powered actuator causes displacement of the spring arm linkageand the seat frame.
 9. The vehicle seat suspension of claim 1 whereinthe fluid powered suspension arrangement comprises a fluid poweredactuator captured in compression between a saddle and a spring armlinkage that is operatively connected to the seat frame.
 10. The vehicleseat suspension of claim 9 further comprising an upright to which thespring arm linkage has one end pivotally attached and a damper attachedto the upright and to the saddle.
 11. The vehicle seat suspension ofclaim 10 wherein the seat frame has a seat portion and a seatbackportion and the spring arm linkage has a pair of arms extendingoutwardly therefrom that are each operatively connected to the seatportion of the seat frame.
 12. A vehicle seat suspension for a vehicleseat comprising: (a) a base; (b) a seat frame; (c) a seat suspensionassembly comprised of a spring arrangement captured in compression andin operable cooperation with the seat frame and the base.
 13. Thevehicle seat suspension of claim 12 wherein seat suspension assemblycomprises a saddle capturing the spring arrangement between the base andthe saddle and a pivotable arm disposed in abutment with the saddle anddisposed in operable cooperation with the seat frame.
 14. The vehicleseat suspension of claim 13 further comprising an upright disposedadjacent or along a rear of the base and a damper coupling the uprightand the saddle.
 15. The vehicle seat suspension of claim 14 wherein theseat frame has a seat portion and a seatback portion and the spring armis generally U-shaped, pivotally attached to the upright, and which hasa pair of outwardly extending arms that each abut a portion of thesaddle and that are each disposed in engagement with the seat portion ofthe seat frame.
 16. The vehicle seat suspension of claim 15 wherein thesaddle carries a pair of rollers that each rotatively support acorresponding one of the spring arms.
 17. The vehicle seat suspension ofclaim 16 wherein the spring arrangement comprises a fluid poweredspring.
 18. The vehicle seat suspension of claim 17 wherein the fluidpowered spring comprises an air spring.
 19. A vehicle seat suspensionfor a vehicle seat comprising: (a) a base comprised of an upright; (b) aseat frame having a seat portion and a seatback portion; (c) a fluidpowered seat suspension arrangement comprising a fluid powered spring, aspring saddle operatively connected to the fluid powered springdisplacing substantially in unison therewith, and a spring arm pivotallyconnected to the upright, in operable cooperation with the saddle, andoperatively connected to the seat portion of the seat frame.
 20. Thevehicle seat suspension of claim 19 wherein the spring arm has aplurality of arms, the saddle carries a plurality of rollers that eachrotatively supports a corresponding one of the spring arms, and whereineach one of the spring arms is operatively connected to the seat portionof the seat frame inwardly of the upright and inwardly of the rollers.